1. Field of the Invention
The present invention relates to a non-volatile memory device. More particularly, the present invention relates to a non-volatile memory with an auxiliary circuit that independently processes commands along with a microprocessor control unit.
2. Descriptions of the Related Art
A hard disc is an essential device for a computer, which stores various kinds of data, such as programs, document files, music files, and etc. Conventionally, hard discs that meet the parallel ATA standard are widely used in the computer industry. However, with the improvement of fast transmissions, a new standard has been developed: the serial ATA standard. Although the serial ATA standard has fast transmission, using the serial ATA standard consumes more power than using the conventional parallel ATA standard. As a result, if the serial ATA standard is used, the bus of this hard disc has to operate at a much faster oscillation frequency. Generally, the oscillation frequency is much faster than the oscillation frequency of a conventional hard disc, for example, the bus of a hard disc meeting the SATA standard operates at an oscillation frequency of 3,000 MHz or 1,500 MHZ, and the bus of a conventional hard disc normally operates at an oscillation frequency lower than 133 MHz. That result is greater power consumption.
Some rules of the serial ATA standard allow the bus of this hard disc to get into the rest modes of different levels. For example, the serial ATA standard defines a partial status where the hard disc could wait 10 μs before processing the next operation. Meanwhile, a hard disc getting into the slumber status could wait no longer than 10 ms to process a next operation.
For the current design of non-volatile memory, the non-volatile memory can't transfer data in certain situations, which are denoted as an erasing waiting time, a reading waiting time and a writing waiting time in below. The erasing waiting time, reading waiting time, and writing waiting time are operation time of the non-volatile memory. For the writing waiting time, a typical current flash write procedure comprises the steps of: (A1) sending command/address to the flash memory; (B1) waiting a short time; (C1) transferring data to the flash memory in high speed; (D1) waiting 300 us˜800 us; and (E1) reading a status of the flash memory and completing this writing. The steps A1, B1, D1, or E1 could be parts the writing waiting time.
For the reading waiting time, a typical current flash read procedure comprises steps of: (A2) sending command/address to the flash memory; (B2) waiting a short time: (C2) transferring data from the flash memory in high speed; (D2) reading a status of the flash memory and completing this reading. The steps A2, B2 or D2 could be the reading waiting time.
For the erasing waiting time, a typical current flash erase procedure, it's the time the flash memory can't transfer data during the erase process. Therefore, all steps of erasing could be the erasing waiting time.
Meanwhile, all the operations of the hard disc are controlled by the microprocessor control unit (MCU). For some particular operations, using the MCU may increase the power consumption as well.
Thus, it is important to develop a new hardware and software structure for a hard disc that can save power.